Triode vacuum tube



Jan. 5,1932. w. G. WADE TRIODE VACUUM TUBE Filed Nov.

1 INVENTOR M/afl/ace 6 Mad? WITNESSES:

ATTORNEY and 17 preferably being of molybdenum.

Patented 1....5, 1932 UNITE-D STATES PATENT OFFICE WALLACE G. WADE, 'OF LANCASTER, PENNSYLVANIA, ASSIGNOR TO WESTINGHO'O'SE ELECTRIC & MANUFACTURING- COHPANY, CORPORATION OF PENNSYLVANIA TBIODE VACUUM TUBE Application filed November 22, 1924. Serial No. 751,508

My invention relates. to thermionic discharge. devices and particularly to filamentar cathodes therefor.

object of my invention is to produce a filamentary cathode suitable for the production of a large electron emission.

Another object of my invention is to produce a filamentary cathode of a more rugged construction than cathodes of the prior art.

Another object of my invention is to produce a filamentary cathode adapted for cooperation with a metal container anode for the translationwf relatively large electric powers.

In the prior art of the construction of hi h power thermionic discharge devices, diculty has been experienced in constructing a sufiiciently rugged filamentary cathode to withstand the duty required. It was further found difiicult to attach the ends of the filaments to lead-in wires and to support the filaments in their proper positions.

Other objects and structural details of my invention will be apparent from the following description when read in connection with the accompanying drawing, wherein:

The single fi ure is a longitudinal v iew, partially in sectlon, of a thermionic discharge device embodying a preferred form of my filamentary cathode.

In the drawing, a cylindrical metal anode 1 is attached by a seal 2 to a glass closure 3 which has a reentrant portion 4, and a press 5 thereon. Lead wires 6 and 7 are sealed through press 5 and serve to convey current into the device. Seal wires 6 and 7 are preferably made of tungsten and have welded to the outer end thereof stranded copper leads 8 and 9 for connection to other portions of the ,circuits. A support wire 11, also-preferably of tungsten, is likewise inserted into the press 5.

To the inner ends of seal wires 7 and 6 are attached branched members 12 and 13, and 14 and 15, preferably of molybdenum. These branched wires are preferably attached first by welding to seal wires 6 and 7 and then further strengthened in their attachment by wire wrappings 16 and 17, the wrapping wires 16 The inner ends of the branch wires 12, 13, 14 and are so positioned as to occupy substantially the corners of a square.

15, first by welding, and then the welds are strengthened by additional wrappings of molybdenum wire 21, 22, 23 and 24. This construction brings the filaments into parallel relation, both electrically and mechanically.

The bights of filaments 18 and 19 are preferably supported by spring members and 26 which are attached to the inner end of support wire 11. These springs 25 and 26 are preferably of tungsten and are preferably attached first by welding to support wire 11 and then the weld further is strengthened by a wrapping of wire 27 also preferably of molybdenum.

In the construction of my device, it has been found possible to use tungsten wire of relatively large size, such as wire having a diameter of 0.025 inches and a length of approximately 8 inches.

In the operation ofmy device, it has been found possible, with thissize and length of filament wire, to secure a sufficiently large electron emission for the generation of powers measured in numbers of kilowatts. It has further been found possible to operate for a length of time greater than has previously been possible before the filaments deteriorate and fail, and it has been found that the construction as previously outlined prevents failure at the point of attachment of the filaments, and results in a sufficiently rugged construction to withstand the service required. Y

While I have shown only one embodiment of my invention in the accompanying drawing, it is capable of various changes and modifications without departing from the spirit thereof, and it is desired, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or indicated in the appended claims. f

I claim as my invention:

1. In a tube, an elongated tubular anode member, an elongated cathode structure axially disposed in said tubular anode member and a glass enclosure sealed to said anode member and constituting therewith 'a hermetically closed envelope, said cathode structure comprising three ri id standards of metal sealed to said glass enc osure, and extending into the space of said tubular anode, two of said standards having arms extending therefrom, and a plurality of filaments electrically connected between said arms and the end of the remaining standard.

2. In a hot-cathode electron-discharge tube, an elongated tubular anode member, an elongated cathode structure axially disposed in said tubular anode member and a glass enclosure sealed to said anode member and constituting therewith a hermetically closed envelope, said cathode structure comprising three rigid standards of metal sealed to said glass enclosure, and extending into the space of said tubular anode, two of said standards having arms extending therefrom, and a plurality of looped filaments having their ends supported from said arms and their bights supported from the end of the remaining standard.

3. In a hot-cathode electron-discharge tube, an elongated tubular anode member, an elongated cathode structure axially disposed in said tubular anode member and a glass enclosure sealed to said anode member and constituting therewith a hermetically closed envelope, said cathode structure comprising three rigid standards of electrically conducting metal sealed to said glass enclosure, and extending into the space of said tubular anode, two of said standards being shorter than the remaining standard and having a plurality of electrical conductive arms extending therefrom, and .a plurality of looped filaments having their ends supported by said arms and their bights supported by said remaining standard.

4. In a hot-cathode electron-discharge tube, an elongated tubular anode member, an elongated cathode structure axially disposed in said tubular anode member and a glassenclosure sealed to said anode member and constituting therewith a hermetically closed envelope, said cathode structure 'comprisin three rigid standards of metal supporte by said glass enclosure and extending into the space of said tubular anode, two

of said standards having arms extending therefrom, and a plurality of looped filaments having their ends supported from said arms and their bights supported from the end of the remaining standard.

In testimony whereof, I have hereunto subscribed my name this 20 da of Nov., 1924.

WALLAG G. WADE.

hot-cathode electron-discharge, 

